Navigating PostgreSQL - Views

Views are virtual tables based on the result set of a SQL statement. Think of them as stored queries that can be treated as if they were tables. When you access a view, PostgreSQL runs the underlying query and presents the results. Key Features Abstraction: Views hide query complexity from end users Security: Control access to sensitive data by exposing only specific columns/rows Data Independence: Changes to underlying tables don't affect applications using views Query Reusability: Complex queries can be saved and reused easily Types of Views 1. Standard Views Virtual tables that run their query each time they're accessed Always show current data No additional storage required Ideal for frequently changing data 2. Materialized Views Store the result set physically Must be refreshed to see updated data Excellent for complex queries with infrequently changing data Improve query performance for expensive computations Example CREATE VIEW product_level_sales_of_top_regions AS WITH regional_sales AS ( SELECT region, SUM(amount) AS total_sales FROM orders GROUP BY region ), top_regions AS ( SELECT region, total_sales FROM regional_sales WHERE total_sales > 10000 ORDER BY total_sales desc LIMIT 10 ), prodcut_wise_data as ( SELECT o.region, o.product_id, SUM(o.qty) AS product_units, SUM(o.amount) AS product_sales FROM orders o JOIN top_regions tr on tr.region=o.region GROUP BY o.region, o.product_id ) select * from prodcut_wise_data ; SELECT * FROM product_level_sales_of_top_regions; Notice how the view: Simplifies complex queries by presenting them as tables Provides a way to reuse complex queries Allows for data masking and security by exposing only specific columns/rows Best Practices 1. Naming Conventions Use clear, descriptive names Consider prefixing views (e.g., v_active_customers or suffixing with _view) Document the view's purpose 2. Performance Considerations Use materialized views for compute-intensive queries Index materialized views when appropriate Be cautious with view chaining (views referencing other views) 3. Security Grant minimum necessary permissions Use views to implement row-level security Consider using views for data masking References PostgreSQL Views PostgreSQL Materialized Views What is Incremental View Maintenance (IVM)? Neon: PostgreSQL Views Next Steps In the next parts, we will explore the different types of scans and join strategies in PostgreSQL. Originally published at https://www.adiagr.com

Mar 10, 2025 - 06:08

Views are virtual tables based on the result set of a SQL statement. Think of them as stored queries that can be treated as if they were tables. When you access a view, PostgreSQL runs the underlying query and presents the results.

Key Features

Abstraction: Views hide query complexity from end users
Security: Control access to sensitive data by exposing only specific columns/rows
Data Independence: Changes to underlying tables don't affect applications using views
Query Reusability: Complex queries can be saved and reused easily

Types of Views

1. Standard Views

Virtual tables that run their query each time they're accessed
Always show current data
No additional storage required
Ideal for frequently changing data

2. Materialized Views

Store the result set physically
Must be refreshed to see updated data
Excellent for complex queries with infrequently changing data
Improve query performance for expensive computations

Example

CREATE VIEW product_level_sales_of_top_regions AS
WITH regional_sales AS (
    SELECT
        region,
        SUM(amount) AS total_sales
    FROM
        orders
    GROUP BY
        region
),
top_regions AS (
    SELECT
        region,
        total_sales
    FROM
        regional_sales
    WHERE
        total_sales > 10000
    ORDER BY
        total_sales desc
    LIMIT
        10
), prodcut_wise_data as (
    SELECT
        o.region,
        o.product_id,
        SUM(o.qty) AS product_units,
        SUM(o.amount) AS product_sales
    FROM
        orders o
    JOIN
        top_regions tr on tr.region=o.region
    GROUP BY
        o.region,
        o.product_id
)
select
    *
from
    prodcut_wise_data
;

SELECT * FROM product_level_sales_of_top_regions;

Notice how the view:

Simplifies complex queries by presenting them as tables
Provides a way to reuse complex queries
Allows for data masking and security by exposing only specific columns/rows

Best Practices

1. Naming Conventions

Use clear, descriptive names
Consider prefixing views (e.g., v_active_customers or suffixing with _view)
Document the view's purpose

2. Performance Considerations

Use materialized views for compute-intensive queries
Index materialized views when appropriate
Be cautious with view chaining (views referencing other views)

3. Security

Grant minimum necessary permissions
Use views to implement row-level security
Consider using views for data masking

References

Next Steps

In the next parts, we will explore the different types of scans and join strategies in PostgreSQL.

Originally published at https://www.adiagr.com